Update fold from Vim 8.0 to 8.1

Author: mnishz

doc/fold.jax

@@ -1,4 +1,4 @@
-*fold.txt*      For Vim バージョン 8.0.  Last change: 2016 Jan 02
+*fold.txt*      For Vim バージョン 8.1.  Last change: 2017 Mar 18
 
 
 		VIMリファレンスマニュアル    by Bram Moolenaar

en/fold.txt

@@ -1,4 +1,4 @@
-*fold.txt*      For Vim version 8.0.  Last change: 2016 Jan 02
+*fold.txt*      For Vim version 8.1.  Last change: 2017 Mar 18
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -79,7 +79,7 @@ This will call a function to compute the fold level: >
 	:set foldexpr=MyFoldLevel(v:lnum)
 This will make a fold out of paragraphs separated by blank lines: >
 	:set foldexpr=getline(v:lnum)=~'^\\s*$'&&getline(v:lnum+1)=~'\\S'?'<1':1
-this does the same: >
+This does the same: >
 	:set foldexpr=getline(v:lnum-1)=~'^\\s*$'&&getline(v:lnum)=~'\\S'?'>1':1
 
 Note that backslashes must be used to escape characters that ":set" handles
@@ -203,7 +203,7 @@ and the level given by the marker:
 1. If a marker with the same fold level is encountered, the previous fold
    ends and another fold with the same level starts.
 2. If a marker with a higher fold level is found, a nested fold is started.
-3. if a marker with a lower fold level is found, all folds up to and including
+3. If a marker with a lower fold level is found, all folds up to and including
    this level end and a fold with the specified level starts.
 
 The number indicates the fold level.  A zero cannot be used (a marker with